Biochimica et Biophysica Acta (BBA) - Mucoproteins and Mucopolysaccharides最新文献

• 1.

  1. A method for dissolving and fractionating bovine sclera has been described. High speed homogenization, utilizing double water extraction, separates out the protein-polysaccharide from the sclera. The residue is disolved with pepsin (EC 3.4.4.1) and trypsin (EC 3.4.4.4) and fractionated by dialysis and cold alcohol precipitation.

• 2.

  2. Chondroitin sulfates A, B and C are found as protein-polysaccharide complexes in bovine sclera. No keratosulfate was found in the tissue.

• 3.

  3. No N-acetyl neuraminic acid is present in bovine sclera.

• 4.

  4. Comparison of the fractions of the bovine sclera and bovine nasal cartilage reveals that the tissues are different in composition and structure.

Human and bovine serum orosomucoids and their neuraminidase (EC 3.2.1.18) treated counterparts were characterized with respect to their sedimentation, diffusion, viscosity, and optical rotatory properties at pH 7 in cacodylate buffer. The human and bovine orosomucoids had molecular weights of 41600 and 37000 respectively by the sedimentation diffusion method. Calculations involving the frictional coefficient and viscosity increment indicated that the two orosomucoids were highly hydrated prolate shaped molecules with an axial ratio of 2.5. The removal of sialic acid caused a loss of the water of hydration with an increase of the axial ratio to 5 and no loss of helical structure.

Spore mucopeptide was prepared by autolysis of the cortical structure of Bacillus coagulans spores. Analysis showed that it contained glucosamine, muramic acid, L-alanine, D-glutamic acid, meso-diaminopimelic acid and D-alanine in the molecular proportions 2.8:3:1.6:1.0:1.0:1.0. About 80% of the diaminopimelic acid residues had one amino group which reacted with fluorodinitrobenzene. Alanine in trace amounts was the only N-terminal amino acid detected. The presence of most of the expected free carboxyl and amino groups was confirmed by titration studies. Not all the amino sugar appeared to be N-acetylated. The results are consistent with the proposition that the spore cortical structure consists of a loosely cross-linked matrix bearing a considerable excess of carboxyl groups.

• 1.

  1. Chemical and enzymological studies on neuramin-lactose sulfate have provided supporting evidence for the proposed structure: $\text{O-α-}\text{D}\text{-N-}\text{acetylneuraminyl}\text{-(2→3)-O-β-}\text{D}\text{-}\text{galactopyranosyl}$$\text{6-O-}\text{sulfate}\text{-(1→4)-}\text{D}\text{-}\text{glucopyranose}$.

• 2.

  2. The enzymological studies showed that neuramin-lactose sulfate is hydrolyzed by neuraminidase (EC 3.2.1.18) and that the lactose sulfate moiety of the molecule is resistant to the action of β-galactosidase (EC 3.2.1.23).

• 3.

  3. The chemical studies showed that during periodate oxidation of neuramin-lactose sulfate, the galactosyl moiety was protected, while in the case of lactose sulfate it underwent complete oxidation.

• 4.

  4. Synthetic D-galactose 6-O-sulfate and the galactose sulfate isolated from neuramin-lactose sulfate were found to be identical by paper chromatography, ionophoresis, infrared spectra and lack of formaldehyde production during periodate oxidation.

An examination has been made of a number of ovarian cyst fluid glycoproteins that are sparingly soluble water but are similar in general composition to the readily soluble blood-group specific glycloproteins obtained from the same source. Ultracentrifugal analysis of approx. 0.1% w/v solutions of the sparingly soluble materials indicate that they have much larger sedimentation coefficients (S_20,w) and molecular weights than have the water-soluble glycoproteins. The sparingly soluble substances have more total amino acids and proportionally more aspartic and glutamic acids and cystine and less serine and threonine than have the soluble glycoproteins. The sparingly soluble substances mostly dissolve in buffered (pH 6.8–7.0, 0.05 M) solutions of thioglycolate, sulphite or cysteine, reagents that bring about the scission of -S-S-bonds. The behaviour and properties of the sparingly soluble glycoproteins suggest that they arise through the building up of relatively small glycoproteins to larger macromolecules through the formation of -S-S- intermolecular associations. A number of ways whereby the formation of these sparingly soluble glycoproteins could occur are discussed.

The distribution of β-glucosidase (EC 3.2.1.21) in dormant and germinating conidia of Aspergillus oryzae has been studied. A considerable amount of the bound β-glucosidase is found in the conidia coats of dormant and germinating conidia, and the ratio of bound form to soluble form in the conidia increases as germination proceeds. The bound enzyme is not removed by detergents, EDTA, urea, salts, and β-1,3-glucanase, but sonication is fairly effective. The physical and chemical properties show that the bound enzyme is identical to the soluble enzyme.

Several dialyzable, hydroxyproline-containing glycopeptides have been isolated from human aorta and gingiva, rat skin and guinea pig skin, and partially characterized. It is suggested that they may be associated with the metabolism of reticulin, or of the reticular fibers, of connective tissue.